Stamping of workpieces with a variety of identifying information is required in many applications. For example, workpieces may advantageously include part identifying information stamped thereon to help to ensure that the correct part pieces are used in the correct applications and/or in the correct locations.
Workpieces which are not simply flat and/or are made of strong material can be particularly difficult to stamp with desired identifying information. For example, structural angle workpieces (e.g., angle irons) may have two longitudinal members connected at right angles along an edge (often by bending a single flat longitudinal member along a line extending in the longitudinal direction), and typically are made of strong metals such as steel or iron to provide the strength required in many construction and manufacturing applications.
Machines have, of course, been used which can be used to stamp identifying information on workpieces, usually in a facility where the workpieces are being worked on (e.g., where a long blank is being punched to provide whatever holes are required for the intended use of the part pieces, with individual elements being sheared from the blank to form the individual part pieces). Moreover, due to the difficulty of such stamping, machines separate and apart from the punching and shearing machines have often been provided to accomplish the stamping.
For example, in one prior art stamping machine, a wheel of hardened raised letter stamps is rotated to orient to the proper character next to the workpiece. That character is then pressed against the workpiece one character at a time until all of the characters of the identifying information have been stamped thereon. Another prior art stamping machine places several stamps into one holder, and then stamps the entire identifying information (e.g., part number) at one time.
Both of the above methods and machines fix the stamps rigidly in a frame and require them to be driven up (into the material of the workpiece) to create or stamp the required characters. Driving up of the materials is done with a separate hydraulic cylinder or cylinders. Some designs use a floating head that requires only one cylinder; some use a rigid design that requires one cylinder to raise the stamps from their lowered position up to touch the material and another cylinder to squeeze the material producing the character(s). In either case, the cost of such machines includes not only the stamps themselves, but also the cost of the drive structure to move the stamps up to the workpiece.
The present invention is directed toward overcoming one or more of the problems set forth above.